[jagarra]

Ran into an unusual problem. I started working on my 62 GMC with a 305. The PO had pulled 5 of the plugs and stuffed paper in the holes. I stuck some used plugs in there the other day as plugs so I could wash the engine. Yesterday, since the weather was not bad, I decided to run the valves and do compression check. Removed the driver side valve cover, only to find a push rod not engaging the rocker, it was just loose in there. I installed it back into position, figuring I would see what was up when I adjusted the lash.
I then started removing the plugs to spin the engine. Did the left bank OK, started on the right bank until I got to number 4, the plug the PO had never removed. I could see why. It was tight. I could break it loose just barely, to say it was tight coming out is an understatement. I took all my strength to even loosen the plug out of the cylinder, I must have managed a few complete turns until my long ratchet handle started jumping teeth. I then went to a 1/2 ratchet and it too was jumping teeth. At least it sounded like it was.
Right now I have Kroil in the plug valley hoping it will soak into the threads.
I am not sure if it is cross threaded or just rusty.
Today it rained and was lousy outside, maybe tomorrow, I may have to dig out the impact wrench to spin it out. Hope I don't have to pull the head on this one.